Main results

Substitution of time spent sitting by ambulatory time reduced 24h glucose levels in the Sit Less regimen as compared with Sitting (mean [SEM]: 7.35 [0.19] vs. 7.69 [0.23] mmol/L, P=0.014). No significant difference was seen between the Sit Less and Exercise regimens (Exercise: 7.29 [0.24} mmol/L, P=0.741).

iAUC provides a summary measure of the increase above fasting glucose level during the subsequent 24 h observation period. iAUC reduced significantly from 1974 [324] min*mmol/L in the Sitting regimen to1263 [189] min*mmol/L in the Sit Less regimen (P=0.002). Structured exercise reduced 24h glucose excursion to 1383 [194] min*mmol/L), but this did not significantly differ from the Sitting regimen (p=0.069).

Duration of hyperglycaemia over a 24 h time span was almost halved, from 211 [44] min/day in the Sitting regimen, to 118 [32] min/day in the Sit Less regimen (p=0.002). The Exercise regimen showed intermediate results with 152 [30] min/day.

An 0.5 MET x h/day difference was estimated between Exercise and Sit Less regimens. Energy intake did not differ significantly between the three regimens.

Conclusion

These data show that the Sit Less regimen improved insulin sensitivity, mean 24 h glucose levels, 24h glucose excursions, duration of hyperglycaemia and fasting triacylglycerol levels. In this study, the general effect of the Sit Less regimen on glucose homeostasis tended to be a little more potent than the effect of structured exercise. Insulin sensitivity was more improved after the Sit Less regimen than after the Exercise regimen. In this respect is it interesting to note that during the Exercise regimen participants spent most of the day sitting. It is thus proposed that the duration of non-sitting activities may be more important than the intensity of these activities.

The volume of light-intensity activities in this study was relatively high as compared with what is generally observed in T2DM patients, thus future studies may establish what activity regimen might be more feasible.